Introducing rate control in sending BDDP messages, quarantining ports as they join the network, change API getEnabledPorts().

FL-81 - Don't trust the buffer ID of the PacketIn if the switch has 0 buffers according to it's features reply.

Rewrite of attachment point logic.  Attachmetn points are maintained independent of entities.  Update test cases.  Duplicate Mac test is disabled for the time being.

* IEntityClassifier only returns a single entity class per entity and all
  entities of a device must belong to the same entity class. Semantics for
  multiple classes was unclear.

* IEntityClassifier is now an IFloodlightService to have a cleaner way of
  setting the classifier to use (the classifier needs to be set before
  DeviceManager.startUp() is called).

[BSC-1838]

Refactoring Route class and getRoute() methods to maintain and provide a sequence of switch-ports, rather than links.  Update unit tests accordingly.

Updates to BroadcastTree data structure; Renaming of IRoutingEngineService to IRoutingService; Updates to signatures of IRoutingService interface methods.

Fixed JUnit tests.

Conflicts:

	src/main/java/net/floodlightcontroller/util/TimedCache.java

Rewriting switch cluster computation to return strongly connected components in the presence of unidirectional links.  The notion of internal switchPort is also changed.

Add event history for packet-in and attachment-point